Health groups, including the Obesity Policy Coalition, the Cancer Council and Diabetes Victoria, are hoping to put more fizz into the debate with the release of modelling to show what such a tax could achieve in Australia.

The modelling was based on a 20 per cent tax on soft drink sales.

Jane Martin, from the Obesity Policy Coalition and co-author of the study, published in the journal PLOS One, said a 20 per cent tax on soft drinks would work, and it would also raise $400 million a year to be spent on obesity prevention.

The research also found the tax could also save about $29 million a year in health expenditure.

"There would be a 12.6 per cent decrease in consumption and the flow-on effects from that relatively small decrease across a population over time would result in fewer cases of diabetes, heart disease and stroke and over time it would also save lives," Ms Martin said.

"Around 1,600 lives potentially would be saved over 25 years."

Previous studies showed a 20 per cent tax could also reduce total energy consumption by about 10,000 kilojoules per person per year, cutting body weight by 0.93 kilograms.

Ms Martin said sugary drinks were the largest source of added sugar in Australian children's diets.

"With one-in-four children and 67 per cent of adults now overweight or obese, we need decisive action by government to address the growing health burden of overweight and obesity in this country," she said.

Despite the impact on consumption of the proposed 20 per cent price hike being considerably less — 12.6 per cent — Ms Martin said the tax would be worth it.

She said the research had shown two-thirds of Australians were in favour of the tax.

"Even a small change in consumption can have a big impact over time; a small change in body mass index and weight can have a big impact on someone's health outcomes," she said.

"This would have a bigger impact on people who are high consumers, so particularly young people, and they're more price sensitive.

"The potential to change behaviour in adolescents ... who are high consumers, drink a lot of soft drink, that can be very impactful because that can take them through the rest of their life and change habits early."

University of Queensland researcher Dr Lennert Veerman said Australians in lower socio-economic groups were disproportionately affected by diet-related illnesses and were likely to experience health improvements.

"A sugary drinks tax is not currently on the political agenda in Australia, but this study and international experience suggest it should be considered as part of any tax reform process," he said.

"Policymakers have cited limited available evidence as a barrier to policy progress in the area of taxes on unhealthy foods, so we expect the detail in our study will be useful to them."